Stipe gracile,
often largely below surface of soil; pileus at least sometimes
appendiculate; bulb often
pointed below and usually radicating; spores cylindric to
bacilliform; known from sandy
Atlantic coastal plain north to at least New Jersey and from the
coastal plain of the Gulf of Mexico.

Stipe usually
mostly above ground, with bulb rounded below (probably a single species); pileus not
appendiculate; odor of carrion or chloride of lime; spores (9.5-) 10.2 - 13.8
(-16.0) × (3.8-) 4.2 - 5.8 (-6.5) µm, with Q
= 2.25 - 2.54 (-2.76); described from Florida;
known as far north as the coastal plain of North Carolina and as
far west as the sandy oak-pine forests of eastern Texas.

Note:
At least one entity that appears nearly identical to A.
bisporigera, but differs in failing to react to KOH or
reacting only very weakly has been found repeatedly in the
Chiricahua Mtns. of Arizona (USA) and in the neovolcanic zone of
central Mexico. The typically reacting A. bisporigera
is not known from Arizona. The taxonomic status of the
nonreacting entity (which
has never been described in detail) is undecided.

Note: A single
collection (at the moment, simply called Amanita sp. M35)
from the state of Tlaxcala, Mexico, might be keyed out to
this terminus of the present key. The known
morphological differences with A. ocreata include the shape of the spores (proportionately narrower,
(9.8-) 11.4 - 13.7 (-14.0) ×
(6.8-) 6.9 - 8.5 (-(9.0) µm,
with Q = 1.66). Since
the field notes on A. sp. M35 when fresh indicate that
there was an odor of cheese, it is possible that a hyphomycete
was infecting the basidiocarp (see A.
polypyramis
(Berk. & Curt.) Sacc.); and, since the flesh
reportedly stained yellowish, there may have been a second
parasite present (see A.
subsolitaria
(Murrill) Murrill). This could have distorted
both the shape of the fruiting body and the shape and size of
the spores.
The
single known specimen was sampled for sequencing of the 5’
end of the 28S ribosomal RNA gene. In the
subsequent analysis, Amanita sp. M35 proved basal
to a clade including A. ocreata, but apparently was
distinct from that species (Hallen et al., to appear).

10.

Partial
veil cream or pale yellowish, membranous, but distinctly
thickened; bulb always pointed below; limbate volva upstanding
with notable space separating it from the stipe. Spores
(8.5-) 8.8 - 12.0 (-14,4) × (5.8-) 6.1 - 8.1 (-9.0), with Q =
1.39 - 1.57; found very infrequently, known from southeastern Canada and northern tier
states of the USA (e.g., Michigan and Minnesota) east of the Rockies with Quercus, Tsuga,
Pinus, Larix, or Populus; similar in overall macroscopic
appearance to A. magnivelaris Peck (below), which doesn't turn
yellow with KOH. The present taxon appears to be rather rare.

Amanita
decipiens sensu Lamoureux.

9.

Spores with Q
<1.20. [Possibly the distinguishing of two taxa here is incorrect.]

Note: A.
virosa sensu auct. amer. is simply (or, to
be more conservative, nearly entirely) composed
of 4-spored collections of A. bisporigera.
There seems to be a tendency to shift progressively from
2-spored to 4-spored basidia as the fruiting
season progresses. Molecular work (Hallen et al., to
appear) has indicated that at least one collection from North
America (Virginia, USA) has been found that falls in a
distinct clade with specimens of European A. virosa
Lam. This raises the possibility (among others) that the
European species has been recently imported into the US.
Not enough is known of the European species and A.
bisporigera so that a complete morphological comparison
between the two can be made. They are separable
molecularly.
Spores from northern European collections determined as A. virosasensu stricto
do not differ significantly from those of the 4-spored
collections of A. bisporigera. Spores of the
European material measure: (6.6-) 8.2
- 10.5 (-13.0) × (6.1-) 6.9 - 9.5 (-12.6) µm, with Q
= 1.06 - 1.10. Hence, no rapid morphological
determination method is known that successfully separates
dried collections of unknown origin by region.

11.

Small mushroom;
spores (4.9-) 8.0 - 10.1 (-11.2) × (4.2-) 7.0 -
8.7 (-9.4) µm, with Q = (1.09-) 1.16 -
1.17. Known to the author from the New Jersey Pine Barrens
(Pinus-Quercus forest) from late in the collecting season. Possibly based on
depauperate material of the above.

Amanita sp.
33.

8.

KOH solution not producing a yellow reaction on pileus
or reaction with KOH unknown; spores with average
Q > or = 1.20.

Amanita
verna (Bull. : Fr.)
Lam.
[Not confirmed from region of study and not known to be distinct
from A. decipiens (Trimbach) Andary & Bon.]

[Note: It is
currently argued in European literature that the
common conception of A. verna as a species
that does not turn yellow in KOH may be due to
the application of the name to specimens of A.
phalloides f. alba (see below). It is
noteworthy that my data from white specimens of A.
phalloides from the northwestern U.S.A.
matches very closely with that provided by
Marchand (above). Authors holding this position
believe that taxa recently treated as varieties
of A. verna that stain yellow with KOH are
actually representative of the type variety of A.
verna.]

[Note:
Vittadini’s phrase “totus albus”
is not a name, but a descriptive phrase; and
Vittadini cannot be held to be the original
author of “Agaricus virosus var. albus.”
In fact, there is no such name; Vittadini’s
taxon is “Agaricus virosus var. b.”
Veselý (1934) did not treat this entity as
completely white. He states that when Amanita
phalloides is completely white, it is
properly referred to A. verna or, as he
called it, A. phalloides subsp. verna. RET
thinks that white specimens of A. phalloides
probably do not deserve separate taxonomic treatment. See A.
phalloides, above.]

13.

Spores with Q
> 1.30.

15.

Partial
veil proportionately large and distinctly thickened. Spores: (7.2-) 8.2
- 10.8 (-12.5) × (5.2-) 5.8 - 7.8 (-9.2) µm, with Q = 1.38 - 1.49;
described from New York State, USA; known from
as far north as Prov. Québec. Apparently, often confused
with taxa having thin partial veils.

Note: Yves Lamoureux and
RET have gone over his material and discussed
it repeatedly over several years. They now believe that the
yellow-staining entity is a relatively rare thing and is (at
least) not the
normal form of A. magnivelaris. Temporarily, they call
it A. decipiens sensu Lamoureux, above.

Spores
(of A. elliptosperma): (8.0-) 8.7 - 11.2 (-11.5) ×
(5.8-) 5.9 - 7.5 (-7.8) µm, with Q = 1.40 - 1.50; the various
taxa listed in this "group" were described from the
states of Florida (Murrill's taxa) and North Carolina (Coker's taxa), USA; known
from mixed forest or in association with Oak (Quercus) from
as far north as the state of New York, USA, and well
south into Central America.

Notes:
All the taxa were
described originally as white. Amanita hygroscopica was
described as having pinkish lamellae; however, this is not a
constant character in other Amanita taxa, and RET has seen
numerous shades ranging from white to cream to pink in
gills of species of this group. Amanita gwyniana
was described as having a "chloride of lime" odor;
however, the same (or similar) odor can be detected in fresh
material assignable to A. elliptosperma and A. sp.
S4. This group seems to be
more common, as a whole, than A. magnivelaris.RET has never found any specimen assignable to this
group that turned yellow with KOH. The response to KOH is
omitted from the original descriptions in all cases. The
Murrill taxa were collected in the sandy coastal plain of
Florida and are sometimes based on small specimens, possibly
depauperate examples of the taxa considered to be larger
"taxa."
Unfortunately, the current condition of types is not conducive
to definitive molecular or morphological judgments on taxonomic
synonymy using present methods.
Spore data from my type studies follow:

Spores: (7.3-)
8.4 - 11.2 (-13.5) × (4.9-) 5.5 - 6.8 (-8.5)
µm, with Q = 1.50 - 1.60 (-1.69). Possibly, not
distinct from one or more of the taxa listed in the previous key entry.
Known not to turn yellow with KOH